Exhaust gas treatment systems for treating exhaust gas from an engine of a vehicle may include a particulate filter. If the engine is a diesel engine, then the particulate filter may be referred to as a diesel particulate filter. The particulate filter traps particulate matter, i.e., soot, from the exhaust gas of the engine. The particulate filter may include one or more substrates that define a plurality of apertures, through which the exhaust gas must flow. The particulate matter collects on the substrate as the exhaust gas flows through the apertures. The particulate filter is occasionally regenerated to remove the collected particulate matter. Regeneration of the particulate filter includes heating the particulate filter to a temperature sufficient to burn the collected particulate matter for a time period sufficient to completely burn all of the particulate matter off of the substrates of the particulate filter, which converts the particulate matter to carbon dioxide that dissipates into the atmosphere.
During regeneration of the particulate filter, a control module defines a regeneration temperature setpoint, which is a desired temperature of the exhaust gas upstream of the particulate filter. The regeneration temperature setpoint is defined to achieve the required temperature within the particulate filter needed to burn off the particulate matter from the substrate. The control module controls the operation of the exhaust gas treatment system so that the temperature of the exhaust gas is approximately equal to the regeneration temperature setpoint However, different operating modes of the vehicle, such as when the vehicle is at idle, driving, or coasting, affect the exhaust mass flow through the exhaust gas treatment system, which affects the ability of the control module to bring the actual temperature of the exhaust gas upstream of the particulate filter in line with the desired regeneration temperature setpoint.